1. Field of the Invention
The invention presented herein relates to urinary control using in intra-anal plug electrode assembly for applying a neuromuscular stimulating signal from a battery-powered electronic circuit to the anal sphincter of the user for causing reduction of urinary incontinence.
2. Description of the Prior Art
B. R. Hopkinson and R. Lightwood of England have reported the use of an intra-anal plug electrode assembly constructed of electrically insulative material having a central constricted portion. When positioned to extend above and below the physiological anal sphincter, the constricted portion allowed the assembly to be held in place by closure of the anal sphincter muscle. The plug had circumferential ring electrodes laterally displaced in both directions from the central constricted portion which were connected to a portable battery-operated generator capable of delivering 25 microsecond pulses at a frequency of about 30 Hz. from 0 to 20 volts. The pulses stimulated the sphincter causing it to close. The device was used to treat persons with anal incontinence, urinary incontinence or both. U.S. Pat. No. 3,749,100 to H.A. von der Mosel, indicates the method of choice for functional electrical stimulation (FES) of the sphincter using an intra-anal electrode unit is a square wave having a peak potential not greater than about 10 volts (preferably between 1 and 2 volts) and a frequency in the range from 18 to 90 Hz. The patent indicates that provision was made for adjustment of the load current by the user.
Cardiac Recorders, Ltd., has provided a system for FES using an intra-anal electrode unit which delivers 1 millisecond pulses at a rate of 200 per second with the output controlled by the user allowing the output to be increased gradually when the unit is turned on.
The nature of an FES signal provided by the prior art devices results in a phenomenon known as fatigue and habituation resulting in a decreasing response to such an FES signal. While that FES signal may be effective initially, its effectiveness diminishes quickly with time.